What a New MRI Study Reveals About Enhancing Parenchyma in Women with Extremely Dense Breasts

In a study of over 4,500 women with extremely dense breasts, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) findings revealed that women with a high volume of enhancing parenchyma have a significantly higher risk of breast cancer in comparison to those with a low volume of enhancing parenchyma.

For the study, recently published in Radiology, researchers reviewed DCE-MRI exams from 4,553 women (mean age of 55.7) with extremely dense breasts in order to investigate the impact of quantitative aspects of breast parenchyma on the development of breast cancer.

In their examination of 15 quantitative fibroglandular tissue features, the study authors found that the volume of enhancing parenchyma accounted for 42 percent of the variance and association with breast cancer occurrence. After stratification of these patients into subgroups of low, intermediate, and high enhancing parenchyma volume, the researchers did a multivariable analysis with adjustments for age, BMI, and background parenchymal enhancement (BPE).

The study authors found that women with high enhancing parenchyma volume had a 2.09 hazard ratio (HR) for breast cancer and those with an intermediate enhancing parenchyma volume had a 2.15 HR in comparison to women with low intermediate enhancing parenchyma volume.

A 50-year-old woman who had a high volume of enhancing parenchyma on DCE-MRI (left) had breast cancer detected in a second round of MRI screening. A 51-year-old woman who had a low volume of enhancing parenchyma on DCE-MRI (right) remained cancer-free during six years of follow-up. (Images courtesy of Radiology.)

“Automated identification of quantitative breast parenchyma enhancement features on dynamic contrast-enhanced (DCE) MRI scans could provide added value for assessing breast cancer risk in women with extremely dense breasts,” wrote study co-author Kenneth G.A. Gilhuijs, Ph.D., an associate professor with the Image Sciences Institute at the University Medical Center Utrecht in the Netherlands, and colleagues.

(Editor’s note: For related content, see “New Meta-Analysis Says MRI is Best Supplemental Imaging for Dense Breasts,” “Researchers Note Lack of Benefit with AI in Women with Dense Breasts” and “New ACR Guidelines.Emphasize Earlier Mammography Screening for High-risk Women.”)

In an accompanying editorial, Lars J. Grimm, M.D., MHS, noted a likely commonality between BPE measurements and the parenchymal enhancement factors discussed by Gilhuijs and colleagues. However, Dr. Grimm pointed out that the parenchyma enhancement factors remained predictive for breast cancer after the researchers controlled for BPE influence.

“This demonstrates the value of breast parenchymal measurements and shows that important information can be extracted from the images beyond subjective radiologist assessment of BPE,” noted Dr. Grimm, an associate professor in the Division of Breast Imaging in the Department of Radiology at the Duke University Medical Center.

In regard to study limitations, the study authors noted the findings are restricted to short-term associations between parenchymal features and breast cancer risk due to a six-year follow-up period. They also conceded a lack of information as to the race and ethnicity of the study cohort, which may inhibit general extrapolation of the study findings.